Why do people run higher weight oil in summer?

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Originally Posted by userfriendly


Without using the "I can use a multi grade year round" excuse;

What would be the advantage/disadvantage of running a mono grade engine oil during the summer?
What would be the advantage/disadvantage of running a 0W or 5W multigrade oil in the summer?


Disadvantage of monograde: I have to go seek out a monograde oil to put into my car, there's ALWAYS jugs of 0/5w20 or 5w30 on the shelf. I'm lazy, I just want to grab my oil and filter on a shopping trip and be done with it. I'm also certainly not doing 3 oil changes a year for the now 10,000 miles I drive.

Advantage of monograde: can't really think of one for the average person.

Disadvantage of multi grade: possibly slightly worse HTHS?

Advantage of multi grade: does all the same stuff monograde does, except I don't have to change it when the weather starts changing.
 
Originally Posted by userfriendly
With all the goo goo and ga ga threads about HTHS viscosity, base oil viscosity etc in the last few weeks, lets talk about post permanent shear high temperature protection.
The PDS tells us how the engine oil performs when fresh, but how about towards the end of the oil drain interval?

SAE30 VS 0W40?


That's where UOAs come in... somewhat. I would love to see some HTHS testing on M1 5w-30 after 10k miles.
 
I was thinking more along the lines of a catastrophic engine failure from insufficient MOFT, not the hair splitting comparative UOAs reveal.

Sure, race teams use 0W40, but they don't drain the oil as per OLM.
 
Originally Posted by userfriendly
I was thinking more along the lines of a catastrophic engine failure from insufficient MOFT, not the hair splitting comparative UOAs reveal.

Sure, race teams use 0W40, but they don't drain the oil as per OLM.


MOFT?
 
Originally Posted by userfriendly
With all the goo goo and ga ga threads about HTHS viscosity, base oil viscosity etc in the last few weeks, lets talk about post permanent shear high temperature protection.
The PDS tells us how the engine oil performs when fresh, but how about towards the end of the oil drain interval?


HTHS typically follows KV100 fairly well, so if an oil shears down with mileage I'd say the HTHS is also reduced by a similar degree.

That's why I use 5W-30 instead of xW-20. I want HTHS headrom for any shearing, and for any driving conditions that might elevate oil temperature.
 
Originally Posted by talest
Not sure the disadvantage of running a 0W or 5W multigrade oil in the summer, but running something 0W all year round should give the penultimate start-up protection, whether it is 4 degrees in the North or 124 degrees somewhere in Phoenix.


0W and 5W during a 124 F "cold" start-up in Phoenix is still many times thicker than 20 or 30 weight at 212 F operating temperature. So it will never be too thin to protect the engine during cold start-ups in warm weather, so no real disadvantage.

There's no problem running a 0W-xx or 5W-xx in hot weather, but cold starting problems can happen if running 10W-xx to 20W-xx in very cold weaher. Engine protection depends on the correct xW when cold (pumpability and flow), and depends on the correct xx weight when the engine is at full (and expected max) operating temperature (adequate HTHS and MOFT).
 
Originally Posted by ZeeOSix
Originally Posted by userfriendly
With all the goo goo and ga ga threads about HTHS viscosity, base oil viscosity etc in the last few weeks, lets talk about post permanent shear high temperature protection.
The PDS tells us how the engine oil performs when fresh, but how about towards the end of the oil drain interval?


HTHS typically follows KV100 fairly well, so if an oil shears down with mileage I'd say the HTHS is also reduced by a similar degree.

That's why I use 5W-30 instead of xW-20. I want HTHS headrom for any shearing, and for any driving conditions that might elevate oil temperature.





HTHS percentage loss is around half the KV100 loss
 
Originally Posted by jongies3
Because they're still under the false impression that thicker protects better when it's hot out. Ambient outside temperature has no effect on oil temp. Your cooling system regulates that!
thumbsup2.gif



That's incorrect. Anyone with an oil temperature gauge will confirm this. Yes the cooling system stays roughly the same between winter and summer but in the hot weather your oil temps are definitely a good 20-30F hotter overall. That's roughly equivalent to going down a grade in viscosity.
 
We, or many are always looking for Genie magic in a store bought bottle that in our mind gives our engines the fountain of youth so to speak...it never ends..thicker is better, taller is better, and so on....the next generation will be the same--its a virus we all have,,,IMHOlol
 
Originally Posted by Patman
Originally Posted by jongies3
Because they're still under the false impression that thicker protects better when it's hot out. Ambient outside temperature has no effect on oil temp. Your cooling system regulates that!
thumbsup2.gif



That's incorrect. Anyone with an oil temperature gauge will confirm this. Yes the cooling system stays roughly the same between winter and summer but in the hot weather your oil temps are definitely a good 20-30F hotter overall. That's roughly equivalent to going down a grade in viscosity.


I have to respectfully disagree based on my experience with a caveat. I have a vehicle that has an oil temperature gauge.

When the vehicle is driven "normally" IE not gunning it, going the speed limit, etc. There is little variance in oil operating temperature between 40-80 degrees outside excepting a more rapid temperature increase to the oil's average operating temperature. I think a range of +/- 10 degrees is more accurate.

That being said, if you are stressing the car the cold weather will keep your average oil temp down significantly just because of the delay in heating and slightly more rapid cooling. So in 10 vs 80 degree weather I would second your +/- 20 or 30 degrees when considering average, but not outlier values of high and low.

Which also brings in the protection factor of the oil being too cold to protect as well.

My thought is that the engineers pick a grade that they anticipate changes in grade based on temperature. So if they spec 5w-30, they know it likely drops in viscosity in the warmer weather somewhat and that is within the tolerance that is acceptable to protect the engine.

After all, an engine is a truly dynamic device where identical operating conditions are hard to reproduce.
 
Originally Posted by badduxx


I have to respectfully disagree based on my experience with a caveat. I have a vehicle that has an oil temperature gauge.

When the vehicle is driven "normally" IE not gunning it, going the speed limit, etc. There is little variance in oil operating temperature between 40-80 degrees outside excepting a more rapid temperature increase to the oil's average operating temperature. I think a range of +/- 10 degrees is more accurate.




What I have found is that even when you're not driving it hard, but you're simply stuck in traffic a bit longer, the oil temps will definitely creep up a lot faster and to a higher level when it's 90 degrees outside compared to when it's 30 or 40. So that's why a lot of manufacturers still specify a thicker oil for hotter climates.
 
Originally Posted by Whammo
I have seen a lot of people recommend running a 5w30 instead of a 5w20 in summertime. As far as I know, the engine operating temp isn't going to be higher in the summer. If the manual says 5w20 is fine year round, why mess with it?



The suggestion is predicated upon the assumption that automakers purposely design their engines to suffer catastrophic lubricant related engine failure after a certain number of miles.

They suggest thicker because outside of towing/racing they think it matters.

Some people just don't understand that the temperature of the engine remains within the same operating temp regardless of the outside temperature. Besides cars today typically have an oil/coolant heat exchanger so the coolant is always pulling heat from the oil.
 
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Originally Posted by Patman
Originally Posted by jongies3
Because they're still under the false impression that thicker protects better when it's hot out. Ambient outside temperature has no effect on oil temp. Your cooling system regulates that!
thumbsup2.gif



That's incorrect. Anyone with an oil temperature gauge will confirm this. Yes the cooling system stays roughly the same between winter and summer but in the hot weather your oil temps are definitely a good 20-30F hotter overall. That's roughly equivalent to going down a grade in viscosity.


This has not been my experience. In several cars, I've never seen more than a 10*F difference in operating oil temps between 20*F weather in January and 100*F weather in July using the same oil, brand, and grade. I use an oil temp gauge in most if my vehicles. The only difference is how long it takes the oil to reach that temperature.

In my Tahoe, the oil temp remains 220-225°F when towing the track car regardless of ambient temperature. Note that when I used conventional oils in this engine, the temp difference was greater to around 230°F in summer. Still not more than a 10°F difference.

In fact, the only time I noticed the temp exceed 230°F was when I used a 10w-40 once following this advice. It got to around 238°F. When back to a 5w-30 with the next oil change and the temp settled back down.
 
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Originally Posted by jongies3
Because they're still under the false impression that thicker protects better when it's hot out. Ambient outside temperature has no effect on oil temp. Your cooling system regulates that!
thumbsup2.gif



On a vehicle without a thermostatically controlled oil cooler, ambient temperature can have a pronounced impact on oil temperature.
 
Originally Posted by userfriendly
With all the goo goo and ga ga threads about HTHS viscosity, base oil viscosity etc in the last few weeks, lets talk about post permanent shear high temperature protection.
The PDS tells us how the engine oil performs when fresh, but how about towards the end of the oil drain interval?

SAE30 VS 0W40?


The bigger difference is going to be the formulation of additives, detergents...etc. Oil companies aren't dumping money into improving the performance of obsolete monogrades, they are dumping that money into their higher volume products, which often have to meet demanding OEM testing protocols.
 
I guess I'm wrong assuming that oil formulators use current additive packages in their mono grade engine oil.

Have a look at Chevron and Havoline mono grade PDS compared to the multi grades of the same application.

I didn't realize that mono grades were obsolete.
 
Originally Posted by userfriendly
I guess I'm wrong assuming that oil formulators use current additive packages in their mono grade engine oil.

Have a look at Chevron and Havoline mono grade PDS compared to the multi grades of the same application.

I didn't realize that mono grades were obsolete.


A PDS isn't going to give you formulation detail, so I'm not sure why you are hanging that out there
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Can you provide some specific examples which support your supposition that these generally obsolete grades, given their lack of current applications, are formulated to meet the same performance specifications as their multigrade siblings?

I'm looking at DELO 100 SAE 40 for example:
https://cglapps.chevron.com/sdspds/PDSDetailPage.aspx?docDataId=508152&docFormat=PDF

- Formulated specifically for Detroit Diesel two-strokes
- API CF-2 CF

There is literally NOTHING in that PDS that would lend one to believe it was formulated similarly to say, DELO 400 SAE 15w-40:
https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=415568&docFormat=PDF

- API CJ-4, CI-4 PLUS, CI-4, CH-4, SM
- Cummins CES 20081
- Detroit Diesel DDC Power Guard 93K218
- DEUTZ DQC III-10 LA
- Mack EO-O Premium Plus
- MAN M 3575
- MB-Approval 228.31
- MTU Category 2.1
- Renault VI RLD-3
- Volvo VDS-4
- ZF TE-ML 04C (Approval number ZF001847)
- ZF TE-ML 23B (Approval number ZF001847)

Delo 400 LE SAE 15W-40 meets the requirements of:
• Caterpillar ECF-3, ECF-2
• Ford WSS-M2C171-E
• JASO DH-2
• ACEA European Service Categories E9, E7

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